Multi-cast waveband grooming algorithms in multi-domain optical networks

With the increasing of number of multimedia network applications, multi-cast services are becoming more and more popular. At the same time, the waveband switching technique is proposed to save ports and to reduce the cost of optical cross-connect. However, the existing multi-cast waveband grooming algorithms are mostly limited to single-domain optical networks. The size of optical backbones keeps enlarging, and the backbones are actually divided into multiple independent domains to provide the needed scalability and confidentiality. To solve these problems, the authors propose three heuristic algorithms: per-domain multi-cast grooming (PDMG), virtual topology multi-cast grooming (VTMG) and hierarchical multi-domain multi-cast grooming (HMMG). The main difference between these algorithms is that the inter-domain routing is performed in a different manner; in other words, the routings in PDMG, VTMG and HMMG are computed based on the domain-by-domain fixed routing table, the high layer in the aggregative virtual topology of multi-domains and the hierarchical integrated multi-cast auxiliary graph, respectively. For the intra-domain routing, the three algorithms employ the same method based on an intra-domain multi-cast integrated auxiliary graph. Simulation results show that compared with PDMG and VTMG, HMMG has the best performance in terms of the number of ports saved and the blocking probability.